Nikon MF lens modification query

[abdurrahman_sibahi]

<p>Hello,<br /> I posted this question elsewhere in the internet and didn't come with a satisfactory answer. Answers I got were either contradictory with each other or just didn't make much sense to me.<br /> I have an old lens (18mm f4 AI, specifically) and a Kipon E-mount to F-mount <em>shift</em> adapter. They're both purchased and I have no option of returning either of them, or buying another adapter. (I doubt I will find deeper shift adapters, but I digress.)<br /> Basically, the lens wouldn't lock into the adapter. It would go in, but wouldn't turn to lock. I twisted it in all directions. The adapter doesn't have any extra pins that shouldn't be there. It worked fine with another Nikon lens (AF 50mm f1.8).<br /> <a href="http://imgur.com/a/cXOum">Here is an imgur gallery</a> that shows the adapter and the lens. (excuse the bad phone camera) <br /> I have been told that this large shelf is the Aperture Index. However, it doesn't do anything in the FM2 , and the similar spoke to it on other lenses is much shorter. How will it affect the lens (for future value in case I sell it, or in operation with other Nikon cameras) if I take it to a metal workshop and grind 2mm off it?<br /> Your kind help is appreciated.</p>

[mike_halliwell]

<p>Is the 'shelf'on the lens fouling the adapter preventing it locking? or is it just that it won't turn at all?</p>

<p>EDIT...OK, I think I see what you mean now. The height of the shelf prevents full insertion into the adapter thus preventing rotation.</p>

<p>I think I'd just smoothly grind it off...ensuring non of the grindings get inside!</p>

[jose_angel]

<p>I think the indexing post is only used for matrix metering with dedicated cameras, the FA and the F4 (I wonder if the FG, too, I don`t know). The loss of value will be absolute for those who want an intact lens to be used with them.<br /> I try to remember that all other camera models doesn`t have the mechanical coupling needed, so the post is useless with them.<br /> Notice that the prong is also used to protect the rear element (e.g. when you put the lens over the table); depending on the shape of the rear element and parts it could be interesting or not to remove it.</p>

[paul_wheatland]

<p>I've had a similar problem with early Nikkor lenses that have a thick baffle protecting the rear optic. They do not fit my fotodiox Nikon lens to Olympus adapter. I don't want to grind this baffle off as the lenses in their original state may prove to be slightly more valuable in their original configuration. Sorry this doesn't solve your problem but lets you know the problem may be more common than thought.</p>

[lilly_w]

<p>The ‘big metal shelf marked in red’ serves to protect the rear element – nothing more. It’s not an indexing post. Rather than modify the lens, why not sacrifice the adapter? Assuming 'shelf' clearance is the problem.</p>

[mike_halliwell]

<p>Jose, Very true! </p>

<p>I wonder why it seems so much higher than others? I thought it was the position clock-wise and the width that mattered....not the depth from the flange?</p>

[jose_angel]

<p>Lilly has a very good eye... actually the lens is not a "true" Ai version as I thought (and the OP says), but a previous non-Ai model with some kind of Ai conversion (Ai`d). So it could not be an indexing post.<br /> The post is close to the point where the "real" indexing post should be (angle), but maybe too close to the locking hole to be an f4 lens (it`s difficult to check on the photos). I think Lilly is right.</p>

[abdurrahman_sibahi]

You guys are right. It's the non-AI version, but converted. I didn't even consider that possibility as I didnt feel it mattered. What threw me

off was keh shipping it as AI.

 

This is the AI version http://www.mir.com.my/rb/photography/companies/nikon/nikkoresources/late70nikkor/ultrawides/18mm.htm

 

And this the non-AI www.mir.com.my/rb/photography/companies/nikon/nikkoresources/6070nikkor/ultrawides/18mm.htm

 

The diagrams on the bottom one have that same shelf .. Which actually convinces me it serves no real utility other than what Lilly

mentioned, protecting the rear element when setting the lens on a table. (I tested it)

 

I think I will safely grind it then. Matrix metering wouldn't work anyway with it. Thanks for the help.

[vilk_inc]

<p>any chance you could sell it and get one that would fit? it looks like it might be in great condition... these "adapters" left enough cripples behind, it's getting harder every year to get period lenses undamaged by "fitting" jobs :(</p>

[doc444]

<p>This guy does conversions of older Nikon lenses so you might ask him.<br>

http://www.aiconversions.com/</p>

[keith_b1]

<p>In the third photo, the big metal shelf seems to have been at least partially removed, apparently by a file.</p>

[stefan_g]

Before resorting to using a file, I'd look for screws attaching the ring that

that 'shelf' is part of.